Cooling structure using rigid movable elements

ABSTRACT

An information processing system includes: a processor; a memory; an input/output subsystem; and a bus coupled to the processor, the memory and the input/output subsystem. The system further includes a cooling structure for cooling the processor. The cooling structure consists of: a compressible backing; a plurality of rigid copper elements disposed between the backing and the processor; a first conformable heat-conducting layer disposed over the processor; a second conformable heat-conducting layer disposed between the compressible backing and the rigid elements; a liquid coolant; and a seal for containing the liquid coolant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending, commonly-owned, U.S.application Ser. No. 11/151,905, filed Jun. 14, 2005, which isincorporated by reference herein.

STATEMENT REGARDING FEDERALLY SPONSORED-RESEARCH OR DEVELOPMENT

None.

INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

None.

FIELD OF THE INVENTION

The invention disclosed broadly relates to the field of cooling devicesfor electronic components, and more particularly relates to the field ofheat sinks for microprocessors.

BACKGROUND OF THE INVENTION

During the normal operation of a computer, integrated circuit devicesgenerate significant amounts of heat. This heat must be continuouslyremoved, or the integrated circuit device may overheat, resulting indamage to the device, and possibly, a reduction in operatingperformance. Cooling devices, such as heat sinks, have been used inconjunction with integrated circuit devices in order to avoid suchoverheating. Generally, a passive heat sink in combination with a systemfan has provided a relatively cost-effective cooling solution. Recently,however, the power of integrated circuit devices such as microprocessorshas increased exponentially, resulting in a significant increase in theamount of heat generated by these devices, thereby necessitating a moreefficient cooling solution.

It is becoming extremely difficult to extract the heat generated bysemiconductor devices (processors, in particular) that continue togenerate more and more heat in the same amount of space. Heat istypically extracted by coupling a heat spreader and thermal cap to thesemiconductor and a heat sink. This coupling typically involves athermal paste which serves to not only transfer heat but provide somedegree of mechanical compliance to compensate for dimensional changesdriven by the high temperatures. This paste is often a weak link in thethermal path. Attempts to thin this layer have resulted in failure ofthe layer when it is exposed to dimensional changes due to heat.

One approach to this problem includes the use of spring loaded fingerswith thermal paste in between them and a thermal paste interface to thechip. This solution is limited in performance by the thermal paste andin design by the requirement for consistent spring loading. Liquid metalhas been proposed on its own as a thermal interface material, but couldhave significant difficulty dealing with large z-axis thermally inducedexcursions, requiring some compliance elsewhere in the package or (ifthe largest spacing seen is still thermally acceptable) some sort ofedge reservoir design.

Therefore, a need exists to overcome the problems with the prior art asdiscussed above, and particularly for a way to cool small electronicdevices using a thermally compliant material.

SUMMARY OF THE INVENTION

Briefly, according to an embodiment of the invention an informationprocessing system includes: a processor; a memory; an input/outputsubsystem; and a bus coupled to the processor, the memory and theinput/output subsystem. The system further includes a cooling structurefor cooling the processor. The cooling structure consists of: acompressible backing; a plurality of rigid copper elements disposedbetween the backing and the processor; a first conformableheat-conducting layer disposed over the processor; a second conformableheat-conducting layer disposed between the compressible backing and therigid elements; a liquid coolant; and a seal for containing the liquidcoolant.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the foregoing and other exemplary purposes, aspects, andadvantages, we use the following detailed description of an exemplaryembodiment of the invention with reference to the drawings, in which:

FIG. 1 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements and aplate, according to one embodiment of the present invention.

FIG. 2 is another cross-sectional side view of the cooling structure ofFIG. 1.

FIG. 3 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements,according to one embodiment of the present invention.

FIG. 4 is another cross-sectional side view of the cooling structure ofFIG. 3.

FIG. 5 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements and aliquid, according to one embodiment of the present invention.

FIG. 6 is another cross-sectional side view of the cooling structure ofFIG. 5.

FIG. 7 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements withfins and a plate, according to one embodiment of the present invention.

FIG. 8 is another cross-sectional side view of the cooling structure ofFIG. 7.

FIG. 9 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements witha fin, a plate and a liquid, according to one embodiment of the presentinvention.

FIG. 10 is another cross-sectional side view of the cooling structure ofFIG. 9.

FIG. 11 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements witha fin, a plate, a seal and a liquid, according to one embodiment of thepresent invention.

FIG. 12 is another cross-sectional side view of the cooling structure ofFIG. 11.

FIG. 13 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements witha fin, a plate, liquid inlets/outlets and a liquid, according to oneembodiment of the present invention.

FIG. 14 is another cross-sectional side view of the cooling structure ofFIG. 13.

FIG. 15 is a perspective view of a series of spring elements in astacked arrangement.

FIG. 16 shows the spring elements of FIG. 15 in a tighter stackedarrangement.

FIG. 17 shows the spring elements of FIG. 15 in an even tighter stackedarrangement.

FIG. 18 is a cross-sectional side view of spring elements in a stackedarrangement.

FIG. 19 shows the spring elements of FIG. 18 in a tighter stackedarrangement.

FIG. 20 shows the spring elements of FIG. 18 in an even tighter stackedarrangement.

FIG. 21 shows the spring elements of FIG. 18 in an even tighter stackedarrangement.

FIG. 22 is a perspective view of a spring element.

FIG. 23 is a perspective view of a series of spring elements of FIG. 22in a stacked arrangement.

FIG. 24 shows the spring elements of FIG. 23 in a tighter stackedarrangement.

FIG. 25 shows the spring elements of FIG. 23 in an even tighter stackedarrangement.

FIG. 26 is a cross-sectional side view of spring elements in a stackedarrangement.

FIG. 27 shows the spring elements of FIG. 26 in a tighter stackedarrangement.

FIG. 28 shows the spring elements of FIG. 26 in an even tighter stackedarrangement.

FIG. 29 shows the spring elements of FIG. 26 in an even tighter stackedarrangement.

FIG. 30 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including rod elements and aliquid coolant, according to one embodiment of the present invention.

FIG. 31 is a high level block diagram showing an information processingsystem useful for implementing one embodiment of the present invention.

FIG. 32 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure includes a liquid withvaporizing capability, a compliant membrane and spring elements withfins, according to one embodiment of the present invention.

FIG. 33 is another cross-sectional side view of the cooling structure ofFIG. 32.

FIG. 34 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure includes a container forcontaining a liquid with vaporizing capability, a compliant membrane andspring elements with fins, according to one embodiment of the presentinvention.

FIG. 35 is another cross-sectional side view of the cooling structure ofFIG. 34.

FIG. 36 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure includes a container forcontaining a liquid with vaporizing capability and spring elements withfins, according to one embodiment of the present invention.

FIG. 37 is another cross-sectional side view of the cooling structure ofFIG. 36.

FIG. 38 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure includes a container forcontaining a liquid with vaporizing capability, a compliant membrane andalternating spring elements with fins, according to one embodiment ofthe present invention.

FIG. 39 is another cross-sectional side view of the cooling structure ofFIG. 38.

FIG. 40 is a cross-sectional side view of a cooling structure for areduced-size electronic device, the cooling structure includes acontainer for containing a liquid with vaporizing capability, acompliant membrane and spring elements with fins, according to oneembodiment of the present invention.

FIG. 41 is another cross-sectional side view of the cooling structure ofFIG. 40.

While the invention as claimed can be modified into alternative forms,specific embodiments thereof are shown by way of example in the drawingsand will herein be described in detail. It should be understood,however, that the drawings and detailed description thereto are notintended to limit the invention to the particular form disclosed, but onthe contrary, the intention is to cover all modifications, equivalentsand alternatives falling within the scope of the present invention.

DETAILED DESCRIPTION

In one embodiment of the present invention, an array of high thermalconductivity spring elements (made of copper, for example) with a highpacking density is included, wherein the spring elements are attached toor integrated with a thermally conductive plate having either a flexibleor somewhat rigid top (such as a heat sink or cold cap side). In anotherembodiment of the present invention, the array of spring elements can beeither coupled or placed in contact with (directly or via an interfacematerial) a subject electronic device, such as a semiconductor device.

In another embodiment of the present invention, the array of springelements can be coupled to or integrated with a conformable high thermalconductivity bottom membrane. When coupled with a membrane, the array ofspring elements can have a relatively small contact area that rapidlyincreases in cross section to the full cross section of the springelement. This arrangement prevents the end of the spring elements fromadding unwanted rigidity to the conformable membrane with minimalthermal resistance. Similarly, the narrowing cross-section feature canalso be implemented in the case where the array of spring elements areeither coupled or placed in contact with a subject electronic device.However, if a very thin thermal interface material is present betweenthe array of spring elements and the electronic device and there is highspatial frequency content in the lack of flatness of the electronicdevice surface, it may be desirable to narrow the spring element ends.

In another embodiment of the present invention, if pure perpendicularmotion is desirable upon compression in the case where the array ofspring elements are coupled to or integrated with a conformable highthermo conductivity bottom membrane, the array of spring elements mayhave narrow sections at the ends where they contact a heat sink. Packingdensity can be as high as practical without interference within anexpected compliance range. In another embodiment of the presentinvention, the array of spring elements can be a particular thicknessthrough their entire length.

In another embodiment of the present invention, if the space occupied bythe array of spring elements can be sealed without compromisingcompliance, a thermally conductive liquid (such as liquid metal) can beadded to reduce the thermal path length. In this embodiment, the presentinvention takes advantage of useful thermal and physical characteristicsof liquid metal. Liquid metal is used as a thermal interface materialbetween the array of spring elements and a microprocessor or a platecoupled thereto.

Embodiments of the invention include advantages of providing compliancein a location other than (or in addition to) the gap area between themicroprocessor and the heat conducting portion of the inventionneighboring the microprocessor. The present invention is furtheradvantageous as the forces on the microprocessor exerted by physicalchanges brought on by heat in the x, y, and z directions do not varygreatly.

Further, the present invention allows for z-compliance by utilizing thearray of spring elements. Thus, at least some the embodiments eliminatethe necessity for compliance in a film disposed between themicroprocessor and a heat spreader or heat sink. Additionally, at leastsome embodiments do not require the use of high-viscosity thermal paste,which is not effective in very thin layers.

FIG. 1 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements and aplate, according to one embodiment of the present invention. FIG. 1shows a heat-producing electronic device, a microprocessor 102, locatedalong the bottom of the assembly 100. Disposed on the microprocessor 102is a first layer 104, which can be a solid layer for providing a heatpath from the microprocessor 102 to the upper elements of the assembly100. Examples of a solid heat-conducting layer used for this purpose area thermally conductive adhesive and a solder such as indium. The firstlayer 104 is a planar surface that rests in contact with themicroprocessor 102. In another embodiment of the present invention, thefirst layer 104 can be a conformable high thermal conductivity membranesuch as a copper sheet. In an embodiment where the first layer 104 is amembrane, an additional layer of high thermal conductivity materialwould be disposed between the microprocessor 102 and the membrane.

The cooling structure assembly 100 further includes an array of springelements 110 that contact or are coupled with the first layer 104. Thearray of spring elements 110 comprise a plurality of springs extendingin the upper direction away from the source of the heat, themicroprocessor 102. Each of the array of spring elements 110 draw heataway from the microprocessor 102 and allows the heat to radiate out fromthe increased surface area of the spring elements 110. Each of the arrayof spring elements 110 is comprised of a heat conducting material suchas copper. Further, each of the array of spring elements 110 exhibitsqualities of a spring, which allows for compression and elongation inthe z-direction, i.e., the up and down direction, and in the x,y-directions, i.e., the sideways directions. This provides mechanicalcompliance in accordance with dimensional changes in the microprocessor102 during use. Note that while the spring elements are shown all bentin the same direction, the springs may be bent in alternate directionsto remove any bias. Each of the array of spring elements 110 comprises aspring such as a leaf spring or a helix spring for offering resistancewhen loaded. Each of the array of spring elements 110 provide compliancebetween the top layer 106 and the microprocessor 102 and works to keepthe top layer 106 in close proximity to the microprocessor 102. Thecomposition and shape of each of the array of spring elements 110 isdescribed in greater detail below.

The cooling structure assembly 100 further includes a top layer 106comprising a planar surface, wherein the array of spring elements 110contact the top layer 106. The top layer 106 can be a solid layer forproviding a heat path from the microprocessor 102 to the upper elementsof the assembly 100. The top layer 106 can be a solid heat-conductinglayer such as a thermally conductive adhesive, solder, or solid metalstructure.

FIG. 2 is another cross-sectional side view of the cooling structure ofFIG. 1. FIG. 2 shows the cooling structure assembly 100 comprising thetop layer 106, the first layer 104 and the array of spring elements 110disposed between them. FIG. 2 also shows the microprocessor 102 at thebottom of the cooling structure assembly 100.

FIG. 3 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements,according to one embodiment of the present invention. FIG. 3 shows thecooling structure assembly 300 comprising the top layer 106, themicroprocessor 102 at the bottom of the cooling structure assembly 300and the array of spring elements 110 disposed between them. The coolingstructure assembly 300 of FIG. 3 is similar to the cooling structureassembly 100 of FIG. 1 except for the presence of the first layer 104.

In this embodiment of the present invention, the array of springelements 110 are either coupled or placed in contact with (directly orwithin an interface material) the microprocessor 102. In anotherembodiment, the array of spring elements 110 can have a relatively smallprofile at the end 302 of the spring elements that contact themicroprocessor 102. The profile would rapidly increase in size to thefull cross section of the spring element at the end 304 of the springelements that contact the top layer 106. This arrangement prevents theend 302 of the array of spring elements 110 from adding unwantedrigidity to the microprocessor 102 without any substantial thermalresistance. In another embodiment, if a very thin thermal interfacematerial is present between the array of spring elements 110 and themicroprocessor 102 and there is high spatial frequency content in thelack of flatness of the surface of the microprocessor 102, it may bedesirable to narrow the spring element ends. In another embodiment ofthe present invention, the array of spring elements 110 can be aparticular thickness through their entire length.

FIG. 4 is another cross-sectional side view of the cooling structure ofFIG. 3. FIG. 4 shows the cooling structure assembly 300 comprising thetop layer 106, the microprocessor 102 at the bottom of the coolingstructure assembly 300 and the array of spring elements 110 disposedbetween them. FIG. 5 is a cross-sectional side view of a coolingstructure for an electronic device, the cooling structure includingspring elements and a liquid, according to one embodiment of the presentinvention. FIG. 5 shows the cooling structure assembly 500 comprising atop layer 106, a microprocessor 102 at the bottom of the coolingstructure assembly 500 and an array of spring elements 110 disposedbetween them. Also included is a thermal interface material 502 and aseal 504 for containing the thermal interface material 502. The coolingstructure assembly 500 of FIG. 5 is similar to the cooling structureassembly 300 of FIG. 3 except for the presence of the thermal interfacematerial 502 and the seal 504. In this embodiment of the presentinvention, the array of spring elements 110 are either coupled or placedin contact with (directly or within an interface material) themicroprocessor 102.

The thermal interface material 502 can be a liquid material or anon-rigid solid material. In one embodiment, the thermal interfacematerial 502 is a non-metal liquid, such as oil or water, or a liquidmetal such as mercury, gallium or a gallium alloy such as with tin orindium. A liquid 502 can be sealed with a seal 504 or container so as torestrict the escape of the liquid from the desired area over themicroprocessor 102. The liquid nature of the liquid 502 allows thesubstance to fill the areas created by the gap created between each ofthe spring elements 110. The liquid 502 provides a heat path from themicroprocessor 102 to the upper elements of the assembly 500 as the heattravels from the microprocessor 102 to the top layer 106.

FIG. 6 is another cross-sectional side view of the cooling structure ofFIG. 5. FIG. 6 shows the cooling structure assembly 500 comprising a toplayer 106, a microprocessor 102 at the bottom of the cooling structureassembly 500 and an array of spring elements 110 disposed between them.Also included is a thermal interface material 502 and a seal 504 forcontaining the thermal interface material 502.

FIG. 7 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements withfins and a plate, according to one embodiment of the present invention.FIG. 7 shows the cooling structure assembly 700 comprising the top layer106, the first layer 104 and the array of spring elements 710 disposedbetween them. FIG. 7 also shows the microprocessor 102 at the bottom ofthe cooling structure assembly 700. In another embodiment of the presentinvention, the first layer 104 can be a conformable high thermalconductivity membrane such as a copper sheet. In an embodiment where thefirst layer 104 is a membrane, an additional layer of high thermalconductivity material would be disposed between the microprocessor 102and the membrane. The cooling structure assembly 700 of FIG. 7 issimilar to the cooling structure assembly 100 of FIG. 1 except for thepresence of the elongated fin portion 702 of each of the array of springelements 110.

In another embodiment of the present invention, a coolant would flowbetween and among the array of spring elements 710. The coolant can be aliquid material or a gas material. In one embodiment, the coolant is anon-metal liquid, such as oil or water, or a liquid metal such asmercury, gallium or a gallium alloy such as with tin or indium. Theliquid nature of the liquid allows the substance to fill the areascreated by the gap created between each of the spring elements 710. Theliquid provides a heat path from the microprocessor 102 to the upperelements of the assembly 700 as the heat travels from the microprocessor102 to the top layer 106. The portion 702 of each of the array of springelements 710 comprises a plurality of fins extending in the upperdirection away from the source of the heat, the microprocessor 102. Theinclusion of the fins serves to effectively increase the surface area ofthe surface of the first layer 104, which serves to dissipate heat intoa cooling gas or liquid. Each fin draws heat away from themicroprocessor 102 and allows the heat to be conducted out from theincreased surface area of the fins. The first layer 104 is a planarsurface that rests in contact with the microprocessor 102.

FIG. 8 is another cross-sectional side view of the cooling structure ofFIG. 7. FIG. 8 shows the cooling structure assembly 700 comprising thetop layer 106, the first layer 104 and the array of spring elements 710disposed between them. FIG. 8 also shows the microprocessor 102 at thebottom of the cooling structure assembly 700.

FIG. 9 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements witha fin, a plate and a liquid, according to one embodiment of the presentinvention. FIG. 9 shows the cooling structure assembly 900 comprisingthe top layer 106, the first layer 104 and the array of spring elements710 disposed between them. FIG. 9 also shows the microprocessor 102 atthe bottom of the cooling structure assembly 900, a cooling gas orliquid 902 (i.e., coolant), a seal 904 and a cooling gas or liquidinlet/outlet pair 906 and 908. The cooling structure assembly 900 ofFIG. 9 is similar to the cooling structure assembly 700 of FIG. 7 exceptfor the provisions for handling a coolant 902, such as seal 904 andinlet/outlet pair 906 and 908. The cooling structure 900 can alsoinclude a pair of flow-restricting end-plates (not shown in this figurebut described in greater detail below).

The coolant 902 can be a gas, a non-metal liquid material, such as oilor water, or a metal liquid material such as mercury, gallium or agallium alloy such as with tin or indium. The coolant 902 is describedin greater detail with reference to FIG. 7 above. FIG. 9 also shows aninlet/outlet pair 906 and 908 for allowing ingress and egress of thecoolant 902. The inlet 906 allows for the intake of the coolant 902 asit is pumped or otherwise pushed or propelled into the assembly 900. Asthe coolant 902 travels in the space filling the areas created by thegap created between the microprocessor 102 and the top layer 106, thecoolant 902 absorbs the heat emanated from the first layer 104 and thearray of spring elements 710, including the fin structure 702. Theoutlet 908 allows for the egress of the coolant 902 as it is pumped orotherwise pulled or propelled out of the assembly 900 for cooling andeventual recycling into the assembly 900.

FIG. 10 is another cross-sectional side view of the cooling structure ofFIG. 9. FIG. 10 shows the cooling structure assembly 900 comprising thetop layer 106, the first layer 104 and the array of spring elements 710disposed between them. FIG. 10 also shows the microprocessor 102 at thebottom of the cooling structure assembly 900, a coolant 902 and a seal904. The cooling structure 900 can also include a pair offlow-restricting end-plates 1002 and 1004 that fill the area on eitherend of the array of spring elements 710 in FIG. 10. The purpose of theend-plates 1002 and 1004 is to restrict the flow of the coolant 902 intothose spaces so as to force the coolant 902 to flow in the area betweenthe multiple spring elements, which is where a higher degree of heatdissipation occurs.

FIG. 11 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements witha fin, a plate, a seal and a liquid, according to one embodiment of thepresent invention. FIG. 11 shows the cooling structure assembly 1100comprising the top layer 106, the first layer 104 and the array ofspring elements 710 disposed between them. FIG. 11 also shows themicroprocessor 102 at the bottom of the cooling structure assembly 1100,a coolant 902, a seal 904, an internal seal 1106 and a liquidinlet/outlet pair 1102 and 1104. The cooling structure assembly 1100 ofFIG. 11 is similar to the cooling structure assembly 900 of FIG. 9except for the presence of the internal seal 1106 and the liquidinlet/outlet pair 1102 and 1104. The cooling structure 1100 can alsoinclude a pair of flow-restricting end-plates (not shown in this figurebut described in greater detail below).

The internal seal 1106 provides a seal within the space filling theareas created by the gap created between the microprocessor 102 and thetop layer 106. The internal seal 1106 is located at a point in thecooling structure assembly 1100 where the fin structures 702 of thearray of spring elements 710 end. That is, the height of the internalseal 1106 is the height at which the fin structure 702 ends and thespring portion begins, for each of the array of spring elements 710.This is the ideal location for the internal seal 1106, as it forces thecoolant 902 to travel within the area of the fin structures 702 of thearray of spring elements 710, which is where a higher degree of heatdissipation occurs in the cooling structure assembly 1100.

FIG. 11 also shows an inlet/outlet pair 1102 and 1104. The inlet 1102allows for the intake of the coolant 902 as it is pumped or otherwisepushed or propelled into the assembly 1100. As the coolant 902 travelsin the space filling the areas created by the gap created between themicroprocessor 102 and the top layer 106 (namely, the area of the finstructures 702 of the array of spring elements 710), the coolant 902absorbs the heat emanated from the first layer 104 and the finstructures 702 of the array of spring elements 710. The outlet 1104allows for the egress of the coolant 902 as it is pumped or otherwisepulled or propelled out of the assembly 1100 for cooling and eventualrecycling into the assembly 1100.

FIG. 12 is another cross-sectional side view of the cooling structure ofFIG. 11. FIG. 12 shows the cooling structure assembly 1100 comprisingthe top layer 106, the first layer 104 and the array of spring elements710 disposed between them. FIG. 12 also shows the microprocessor 102 atthe bottom of the cooling structure assembly 1100, a thermal interfacematerial 902, a seal 904 and an internal seal 1106. The coolingstructure 1100 can also include a pair of flow-restricting end-plates1202 and 1204 that fill the area on either end of the array of springelements 710 in FIG. 12. The purpose of the end-plates 1202 and 1204 isto restrict the flow of the coolant 902 into those spaces so as to forcethe coolant 902 to flow in the area between the multiple springelements, which is where a higher degree of heat dissipation occurs.

FIG. 13 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure including spring elements witha fin, a plate, inlets/outlets and a coolant, according to oneembodiment of the present invention. FIG. 13 shows the cooling structureassembly 1300 comprising the top layer 106, the first layer 104 and thearray of spring elements 710 disposed between them. FIG. 13 also showsthe microprocessor 102 at the bottom of the cooling structure assembly1100, a coolant 902, a seal 904 and a series of inlets/outlets. Thecooling structure assembly 1300 of FIG. 13 is similar to the coolingstructure assembly 1100 of FIG. 11 except for the presence of the seriesof inlets/outlets and the lack of the internal seal 1106. The coolingstructure 1300 can also include a pair of flow-restricting end-plates(not shown in this figure but described in greater detail below).

FIG. 13 also shows a series of inlets/outlets. Orifices 1302, 1304,1306, 1308, 1310 and 1312 are designated as inlets. Orifices 1314, 1316,1318, 1320 and 1322 are designated as outlets. The inlets allow for theintake of the coolant 902 as it is pumped or otherwise pushed orpropelled into the assembly 1300. As the coolant 902 travels in thespace filling the areas created by the gap created between themicroprocessor 102 and the top layer 106 (namely, the area of the arrayof spring elements 710), the coolant 902 absorbs the heat emanated fromthe first layer 104 and the array of spring elements 710. The outletsallow for the egress of the coolant 902 as it is pumped or otherwisepulled or propelled out of the assembly 1300 for cooling and eventualrecycling into the assembly 1300.

FIG. 14 is another cross-sectional side view of the cooling structure ofFIG. 13. FIG. 14 shows the cooling structure assembly 1300 comprisingthe top layer 106, the first layer 104 and the array of spring elements710 disposed between them. FIG. 14 also shows the microprocessor 102 atthe bottom of the cooling structure assembly 1300, a coolant 902 and aseal 904. The cooling structure 1300 can also include a pair offlow-restricting end-plates 1402 and 1404 that fill the area on eitherend of the array of spring elements 710 in FIG. 14.

FIG. 15 is a perspective view of a series of spring elements in astacked arrangement. A uniform first distance exists between each springelement. Note each of the spring elements comprises a single sheet ofmaterial, such as a thermally conductive sheet of metal such as copper,that includes sections that are drilled out or removed. The springelements of FIG. 15 are examples of spring elements that can be used inany of the cooling structure assemblies 100, 300, 500, 700, 900, 1100and 1300. The stacked nature of the spring elements of FIG. 15 show howthe spring elements can be arranged for inclusion into any of theaforementioned cooling structure assemblies. Note that FIGS. 15-17 showthe series of spring elements as they are stacked during assembly of amicroprocessor assembly that includes the present invention, in oneembodiment.

FIG. 16 shows the spring elements of FIG. 15 in a tighter stackedarrangement. A uniform second distance exists between each springelement, wherein the second distance is shorter than the first distance.FIG. 17 shows the spring elements of FIG. 15 in an even tighter stackedarrangement. A uniform third distance exists between each springelement, wherein the third distance is shorter than the second distance.

FIG. 18 is a cross-sectional side view of spring elements in a stackedarrangement. A uniform first distance exists between each springelement. Compared to the spring elements of FIG. 15, note that thespring elements of FIG. 18 each include an additional element 1802 onthe top end of the spring elements and an additional element 1804 on thebottom end of the spring elements. Note that FIGS. 18-20 show the seriesof spring elements as they are stacked during assembly of amicroprocessor assembly that includes the present invention, in oneembodiment.

FIG. 19 shows the spring elements of FIG. 18 in a tighter stackedarrangement. A uniform second distance exists between each springelement, wherein the second distance is shorter than the first distance.FIG. 20 shows the spring elements of FIG. 18 in an even tighter stackedarrangement. A uniform third distance exists between each springelement, wherein the third distance is shorter than the second distance.FIG. 21 shows the spring elements of FIG. 18 in an even tighter stackedarrangement. A uniform fourth distance exists between each springelement, wherein the fourth distance is shorter than the third distance.Note in FIG. 21 that the additional element 1802 on the top end of thespring elements and the additional element 1804 on the bottom end of thespring elements has been removed. That is, the spring elements have beentrimmed. Note also that the purpose of the contact regions at the topand bottom of the elements is to set the spacing between the springelements.

FIG. 22 is a perspective view of a spring element. Note that the springelement comprises a single sheet of material, such as a thermallyconductive sheet of metal such as copper, that includes sections thatare drilled out or removed. The spring element of FIG. 15 is an exampleof a spring element that can be used in any of the cooling structureassemblies 100, 300, 500, 700, 900, 1100 and 1300. FIG. 23 is aperspective view of a series of spring elements of FIG. 22 in a stackedarrangement. A uniform first distance exists between each springelement. The stacked nature of the spring elements of FIG. 23 show howthe spring elements can be arranged for inclusion into any of theaforementioned cooling structure assemblies.

FIG. 24 shows the spring elements of FIG. 23 in a tighter stackedarrangement. A uniform second distance exists between each springelement, wherein the second distance is shorter than the first distance.FIG. 25 shows the spring elements of FIG. 23 in an even tighter stackedarrangement. A uniform third distance exists between each springelement, wherein the third distance is shorter than the second distance.

FIG. 26 is a cross-sectional side view of spring elements in a stackedarrangement. A uniform first distance exists between each springelement. Compared to the spring elements of FIG. 23, note that thespring elements of FIG. 26 each include an additional element 2602 onthe top end of the spring elements and an additional element 2604 on thebottom end of the spring elements. FIG. 27 shows the spring elements ofFIG. 26 in a tighter stacked arrangement. A uniform second distanceexists between each spring element, wherein the second distance isshorter than the first distance. FIG. 28 shows the spring elements ofFIG. 26 in an even tighter stacked arrangement. A uniform third distanceexists between each spring element, wherein the third distance isshorter than the second distance. FIG. 29 shows the spring elements ofFIG. 26 in an even tighter stacked arrangement. A uniform fourthdistance exists between each spring element, wherein the fourth distanceis shorter than the third distance. Note in FIG. 29 that the additionalelement 2602 on the top end of the spring elements and the additionalelement 2604 on the bottom end of the spring elements has been removed.

FIG. 30 is a cross-sectional side view of a cooling structure 3000 foran electronic device. The cooling structure 3000 includes rod elements3020 and a liquid coolant 3024, according to one embodiment of thepresent invention. FIG. 30 shows a heat-producing electronic device3002, such as a microprocessor, located along the bottom of the assembly3000. The microprocessor 3002 is disposed, such as through welding orsoldering, onto a circuit board 3030. An attachment 3022 surrounds themicroprocessor 3002 and provides a base for placing a rigid structure3028 such that it is located above or over the microprocessor 3002. Thestructure 3010 is also a rigid structure that may be integrated with orseparate from the rigid structure 3028.

Disposed on the microprocessor 3002 is a first layer 3004, which is aconformable high thermo conductivity membrane for providing a heat pathfrom the microprocessor 3002 to the upper elements of the assembly 3000.The first layer 3004 is a planar surface that rests in contact with themicroprocessor 3002. Disposed above the first layer 3004 is a secondlayer 3006, which can also be a conformable high thermo conductivitymembrane for providing a heat path from the microprocessor 3002 to theupper elements of the assembly 3000. The second layer 3006 is a planarsurface that rests in contact with a compressible material layer 3008,such as rubber. The layer 3006 is used as an adhesion/water-seal layerthat is soft or pliable.

The term membrane refers to a thin substrate used to separate differentlayers or materials. There is no inherent application of tension assumedin conjunction with use of this term. The membranes described above canbe foils or flexible sheets.

The cooling structure assembly 3000 further includes an array of rigidrod elements 3020 that contact or are coupled with the first layer 3004and the second layer 3006. The array of rigid rod elements 3020 aredisposed between the first layer 3004 and the second layer 3006. Thearray of rod elements 3020 comprises a plurality of rods or smallcylinders extending in a direction away from the source of the heat, themicroprocessor 3002. Each of the array of rod elements 3020 draw heataway from the microprocessor 3002 and allows the heat to radiate outfrom the increased surface area of the rod elements 3020. Each of thearray of rod elements 3020 comprises a semi-rigid, high thermalconductivity material, such as copper. Further, the array of rodelements 3020 are packed densely. Equivalently, a set of fins can beused in place of the rods.

Due to the conformable nature of the first layer 3004 and the secondlayer 3006, each individual rod element has the freedom to move upwardsor downwards. Further, due to the compressible nature of thecompressible material layer 3008, each individual rod element has thefreedom to move upwards into the compressible material layer 3008 ordownwards away from compressible material layer 3008, as the dimensionsof the microprocessor 3002 change due to heat buildup during use. Thus,the compressible material layer 3008 allows for compression andelongation in the z-direction, i.e., the up and down direction, and inthe x, y-directions, i.e., the sideways directions. This provides heatcompliance in accordance with dimensional changes in the microprocessor102 during use.

FIG. 30 also shows that a thermal interface material 3024 can be locatedin the gap created between the structure 3010 and the structure 3028 andin the area between first layer 3004 and the second layer 3006. Thethermal interface material 3024 can be a non-metal liquid thermalinterface material, such as oil or water, or a metal liquid thermalinterface material such as mercury, gallium or a gallium alloy such aswith tin or indium. The liquid 3024 can be sealed so as to restrict theescape of the liquid from the desired area over the microprocessor 3002.The liquid nature of the liquid 3024 allows the substance to fill theareas created by the gap created between the structure 3010 and thestructure 3028 and in the area between first layer 3004 and the secondlayer 3006. The liquid 3024 provides a heat path from the microprocessor3002 to the upper elements of the assembly 3000 as the heat travels fromthe microprocessor 3002 upwards.

FIG. 30 also shows a liquid inlet/outlet pair 3016 and 3018. The liquidinlet 3016 allows for the intake of the liquid thermal interfacematerial 3024 as it is pumped or otherwise pushed or propelled into theassembly 3000. As the liquid thermal interface material 3024 travels inthe space filling the areas created by the gap created between thestructure 3010 and the structure 3028 and in the area between firstlayer 3004 and the second layer 3006, the liquid thermal interfacematerial 3024 absorbs the heat emanated from the first layer 3004 andthe array of rod elements 3020. The liquid outlet 3018 allows for theegress of the liquid thermal interface material 3024 as it is pumped orotherwise pulled or propelled out of the assembly 3000 for cooling andeventual recycling into the assembly 3000.

FIG. 32 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure includes a liquid withvaporizing capability, a compliant membrane and spring elements withfins, according to one embodiment of the present invention.

FIG. 32 shows the cooling structure assembly 3200 comprising a top layer3206, a microprocessor 3202 at the bottom of the cooling structureassembly 3200 and an array of spring elements 3210 disposed betweenthem. In the space between the top layer 3206 and the microprocessor3202 is the presence of a vaporizing liquid 3201. The cooling structureassembly 3200 of FIG. 32 is similar to the cooling structure assembly500 of FIG. 5 except for the presence of the vaporizing liquid 3201 andthe wicking capabilities of the spring elements 3210. Wicking can begenerated by the surface tension in the narrow spaces between theelements and/or by porous coatings in the surfaces of the elements. Inthis embodiment of the present invention, the array of spring elements3210 are coupled or placed in contact with a compliant interfacesubstrate 3203 disposed over the microprocessor 3202.

The liquid 3201 can be any liquid that can be used to cool themicroprocessor 3202, including any commercially availablemicroprocessor. Such a liquid 3201 can have qualities such that itevaporates or vaporizes at temperatures that are normally reached by themicroprocessor 3202 during use. The vapor typically moves upwards towardthe top layer 3206 and away through the spaces between the springelements, areas which are further away from the microprocessor 3202 andthus at a lower temperature. This leads to condensation whereby thevapor returns to liquid form. Upon returning to liquid form, thesubstance is pulled by wicking forces and/or gravity back into the areaabove the microprocessor 3202 whereby the liquid 3201 resumes its heatabsorbing function. The spring portion of the array of spring elements3210 may serve as a pathway for returning the condensed liquid 3201 tothe area above the microprocessor 3202. The larger diameter passagewaysformed near the base of the elements 3210 where they narrow and attachto membrane 3203 provide low resistance flow channels to allow fluid3201 to distribute easily across the stack of elements 3210.

The liquid 3201 can be sealed with a seal or container so as to restrictthe escape of the liquid from the desired area over the microprocessor3202. The liquid nature and surface tensions of the liquid 3201 allowsthe substance to fill the areas created by the gap created between eachof the spring elements 3210. The lower portions of the spring elements3210 provide a heat path into the liquid, causing vaporization as wellas providing a conduction path to the top surface 3206.

FIG. 33 is another cross-sectional side view of the cooling structure ofFIG. 32. The cooling structure assembly 3200 of FIG. 33 is similar tothe cooling structure assembly 600 of FIG. 6 except for the presence ofthe vaporizing liquid 3201 and the wicking capabilities of the springelements 3210.

FIG. 34 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure includes a container forcontaining a liquid with vaporizing capability, a compliant membrane andspring elements with fins, according to one embodiment of the presentinvention.

FIG. 34 shows the cooling structure assembly 3400 comprising a top layer3406, a microprocessor 3402 at the bottom of the cooling structureassembly 3400 and an array of spring elements 3410 disposed betweenthem. The cooling structure assembly 3400 of FIG. 34 is similar to thecooling structure assembly 500 of FIG. 5 except for the presence of avaporizing liquid, the wicking capabilities of the spring elements 3410and the seal 3430. In this embodiment of the present invention, thearray of spring elements 3410 are either coupled or placed in contactwith (directly or within an interface material) the microprocessor 3402.

In the space between the top layer 3406 and the microprocessor 3402 canbe a vaporizing liquid, identical to the liquid 3201 above. The liquidcan be sealed with a seal 3430 or container so as to restrict the escapeof the liquid from the desired area over the microprocessor 3402. Theliquid nature of the liquid allows the substance to fill the areascreated by the gap created between each of the spring elements 3410. Thelower portions of the spring elements 3410 provide a heat path into theliquid, causing vaporization as well as providing a conduction path tothe top surface 3406.

In another embodiment of the present invention, the cooling structureincludes a condenser coupled to the seal 3430, whereby the condenserallows the liquid in a vaporized form to enter into the condenser,condense into a liquid form and then exit the condenser and return tothe space contained by seal 3430.

FIG. 35 is another cross-sectional side view of the cooling structure ofFIG. 34. The cooling structure assembly 3400 of FIG. 35 is similar tothe cooling structure assembly 600 of FIG. 6 except for the presence ofa vaporizing liquid, the wicking capabilities of the spring elements3410 and the seal 3430.

One embodiment of the invention comprises creating a locally andglobally compliant cooling structure with an integrated vapor chambermade of a high thermal conductivity material, such as copper, whereinthe vapor chamber structure wicks the liquid, heats and evaporates theliquid into vapor, and includes liquid return paths when the vaporcondenses. At least some embodiments allow the use of very thin thermalinterface materials of lower thermal conductivity. At least someembodiments provide reasonable compliance in the X-Y plane as well dueto the thin bottom layer 3403. Virtually any thermal interface material(TIM) may be used. A heat-generating electronic device package can becreated with a much larger surface area to which a heat sink or cold capcan be coupled. This provides for very high heat removal capability.

At least some embodiments comprise creating an array of high thermalconductivity (such as copper) elements comprising both a spring portion(potentially doubling as a liquid return path) and a wicking fin portionwith a high packing density attached to or integrated into either aflexible or relatively rigid top plate.

The wicking fin portion can also provide liquid distribution channelsbelow the surface of the evaporating liquid, for lower pressure drop andhigher peak heat transfer capability. The aforementioned elements arealso attached to/integrated into a conformable high thermal conductivitybottom (i.e., chip-side) membrane. When attached to a membrane, thespring elements have a small contact area that rapidly increase in crosssection to the full cross section of the spring elements. This preventsthe ends of the spring elements from adding unwanted rigidity to theconformable membrane without adding substantial thermal resistance.Packing density is as high as practical without interference within theexpected compliance range while maintaining vapor chamber performance.Packing density and surface finish in the wicking region can beoptimized to improve capillary action and provide enhancedheat-transfer/boiling surfaces.

In an embodiment of the present invention, the spring elements can havea particular thickness through their entire length, unlike what is shownin the FIGS. 32-35.

In another embodiment of the present invention, while the spring andwicking portions can comprise differing sections of each array element,as shown in FIG. 32, the functions of wicking and spring force can bemore integrated. Such an arrangement serves to separately optimize thebehavior of each section (spring and wicking) of the array elements.

FIG. 34 shows one implementation for sealing the apparatus and allowingfor liquid return paths within the array assembly. FIG. 34 shows thevapor chamber significantly larger than the chip. This implementationprovides for a larger contact area for the heat sink or cold cap andallows more reservoir space that is not in close proximity to the chip.Note that nothing prevents the use of a separate condenser by routingthe vapor away to the condenser and returning the condensate to thewicking area.

FIG. 36 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure includes a container forcontaining a liquid with vaporizing capability and spring elements withfins, according to one embodiment of the present invention.

FIG. 36 shows the cooling structure assembly 3600 comprising a top layer3606, a microprocessor 3602 at the bottom of the cooling structureassembly 3600 and an array of spring elements 3610 disposed betweenthem. The cooling structure assembly 3600 of FIG. 36 is similar to thecooling structure assembly 500 of FIG. 5 except for the presence of avaporizing liquid, the wicking capabilities of the spring elements 3610and the seal 3630. In this embodiment of the present invention, thearray of spring elements 3610 are either coupled or placed in contactwith (directly or within an interface material) the microprocessor 3602.

In the space between the top layer 3606 and the microprocessor 3602 canbe a vaporizing liquid, identical to the liquid 3601 above. The liquidcan be sealed with a seal 3630 or container so as to restrict the escapeof the liquid from the desired area over the microprocessor 3602 and tomaintain the liquid and vapor separate from the external atmosphere asit's pressure may be substantially different from atmospheric pressure.The nature of the liquid allows the substance to fill the areas createdby the gap created between each of the spring elements 3610. The liquidprovides a heat path from the microprocessor 3602 to the upper elementsof the assembly 3600 as the heat travels from the microprocessor 3602 tothe top layer 3606.

In another embodiment of the present invention, the cooling structureincludes a condenser coupled to the seal 3630, whereby the condenserallows the liquid in a vaporized form to enter into the condenser,condense into a liquid form and then exit the condenser and return tothe space contained by seal 3630. Additional seal 3603 provides a sealfor the liquid 3601 at the juncture between the microprocessor 3602 andthe seal 3630.

FIG. 37 is another cross-sectional side view of the cooling structure ofFIG. 34. The cooling structure assembly 3600 of FIG. 37 is similar tothe cooling structure assembly 600 of FIG. 6 except for the presence ofa vaporizing liquid, the wicking capabilities of the spring elements3610 and the seal 3630.

FIG. 38 is a cross-sectional side view of a cooling structure for anelectronic device, the cooling structure includes a container forcontaining a liquid with vaporizing capability, a compliant membrane andalternating spring elements with fins, according to one embodiment ofthe present invention.

FIG. 38 shows the cooling structure assembly 3800 comprising a top layer3806, a microprocessor 3802 at the bottom of the cooling structureassembly 3800 and an array of spring elements 3810 disposed betweenthem. The cooling structure assembly 3800 of FIG. 38 is similar to thecooling structure assembly 500 of FIG. 5 except for the presence of avaporizing liquid, the wicking capabilities of the spring elements 3810and the seal 3830. In this embodiment of the present invention, thearray of spring elements 3810 are either coupled or placed in contactwith (directly or within an interface material) the microprocessor 3802.

In the space between the top layer 3806 and the microprocessor 3802 canbe a vaporizing liquid, identical to the liquid 3801 above. The liquidcan be sealed with a seal 3830 or container so as to restrict the escapeof the liquid from the desired area over the microprocessor 3802. Theliquid nature of the liquid allows the substance to fill the areascreated by the gap created between each of the spring elements 3810. Theliquid provides a heat path from the microprocessor 3802 to the upperelements of the assembly 3800 as the heat travels from themicroprocessor 3802 to the top layer 38606.

In another embodiment of the present invention, the spring elements 3810alternate in length and size, as shown by alternating spring elements3850 and 3851.

FIG. 39 is another cross-sectional side view of the cooling structure ofFIG. 38. The cooling structure assembly 3800 of FIG. 39 is similar tothe cooling structure assembly 600 of FIG. 6 except for the presence ofa vaporizing liquid, the wicking capabilities of the spring elements3810 and the seal 3830.

FIG. 40 is a cross-sectional side view of a cooling structure for areduced-size electronic device, the cooling structure includes acontainer for containing a liquid with vaporizing capability, acompliant membrane and spring elements with fins, according to oneembodiment of the present invention.

FIG. 40 shows the cooling structure assembly 4000 comprising a top layer4006, a microprocessor 4002 at the bottom of the cooling structureassembly 4000 and an array of spring elements 4010 disposed betweenthem. The cooling structure assembly 4000 of FIG. 40 is similar to thecooling structure assembly 500 of FIG. 5 except for the presence of avaporizing liquid, the wicking capabilities of the spring elements 4010and the seal 4030. In this embodiment of the present invention, thearray of spring elements 4010 are either coupled or placed in contactwith (directly or within an interface material) the microprocessor 4002.

In the space between the top layer 4006 and the microprocessor 4002 canbe a vaporizing liquid, identical to the liquid 3201. The liquid can besealed with a seal 4030 or container so as to restrict the escape of theliquid from the desired area over the microprocessor 4002. The liquidnature and surface tension of the liquid allows the substance to fillthe areas created by the gap created between each of the spring elementsThe lower portions of the spring elements 4010 provide a heat path intothe liquid, causing vaporization as well as providing a conduction pathto the top surface 4006.

In another embodiment of the present invention, the cooling structureincludes a condenser coupled to the seal 4030, whereby the condenserallows the liquid in a vaporized form to enter into the condenser,condense into a liquid form and then exit the condenser and return tothe space contained by seal 4030.

FIG. 41 is another cross-sectional side view of the cooling structure ofFIG. 40. The cooling structure assembly 4000 of FIG. 41 is similar tothe cooling structure assembly 600 of FIG. 6 except for the presence ofa vaporizing liquid, the wicking capabilities of the spring elements4010 and the seal 4030.

Embodiments of the invention can be utilized for cooling any of avariety of electronic devices. For example, one embodiment is used tocool a microprocessor of an information processing system such as acomputer. FIG. 31 is a high level block diagram showing an informationprocessing system useful for implementing one embodiment of the presentinvention. The computer system includes one or more processors, such asprocessor 3104. The processor 3104 is connected to a communicationinfrastructure 3102 (e.g., a communications bus, cross-over bar, ornetwork). Various software embodiments are described in terms of thisexemplary computer system. After reading this description, it willbecome apparent to a person of ordinary skill in the relevant art(s) howto implement the invention using other computer systems and/or computerarchitectures.

The computer system can include a display interface 3108 that forwardsgraphics, text, and other data from the communication infrastructure3102 (or from a frame buffer not shown) for display on the display unit3110. The computer system also includes a main memory 3106, preferablyrandom access memory (RAM), and may also include a secondary memory3112. The secondary memory 3112 may include, for example, a hard diskdrive 3114 and/or a removable storage drive 3116, representing a floppydisk drive, a magnetic tape drive, an optical disk drive, etc. Theremovable storage drive 3116 reads from and/or writes to a removablestorage unit 3118 in a manner well known to those having ordinary skillin the art. Removable storage unit 3118, represents a floppy disk, acompact disc, magnetic tape, optical disk, etc. which is read by andwritten to by removable storage drive 3116. As will be appreciated, theremovable storage unit 3118 includes a computer readable medium havingstored therein computer software and/or data.

In alternative embodiments, the secondary memory 3112 may include othersimilar means for allowing computer programs or other instructions to beloaded into the computer system. Such means may include, for example, aremovable storage unit 3122 and an interface 3120. Examples of such mayinclude a program cartridge and cartridge interface (such as that foundin video game devices), a removable memory chip (such as an EPROM, orPROM) and associated socket, and other removable storage units 3122 andinterfaces 3120 which allow software and data to be transferred from theremovable storage unit 3122 to the computer system.

The computer system may also include a communications interface 3124.Communications interface 3124 allows software and data to be transferredbetween the computer system and external devices. Examples ofcommunications interface 3124 may include a modem, a network interface(such as an Ethernet card), a communications port, a PCMCIA slot andcard, etc. Software and data transferred via communications interface3124 are in the form of signals which may be, for example, electronic,electromagnetic, optical, or other signals capable of being received bycommunications interface 3124. These signals are provided tocommunications interface 3124 via a communications path (i.e., channel)3126. This channel 3126 carries signals and may be implemented usingwire or cable, fiber optics, a phone line, a cellular phone link, an RFlink, and/or other communications channels.

In this document, the terms “computer program medium,” “computer usablemedium,” and “computer readable medium” are used to generally refer tomedia such as main memory 3106 and secondary memory 3112, removablestorage drive 3116, a hard disk installed in hard disk drive 3114, andsignals. These computer program products are means for providingsoftware to the computer system. The computer readable medium allows thecomputer system to read data, instructions, messages or message packets,and other computer readable information from the computer readablemedium. The computer readable medium, for example, may includenon-volatile memory, such as a floppy disk, ROM, flash memory, diskdrive memory, a CD-ROM, and other permanent storage. It is useful, forexample, for transporting information, such as data and computerinstructions, between computer systems. Furthermore, the computerreadable medium may comprise computer readable information in atransitory state medium such as a network link and/or a networkinterface, including a wired network or a wireless network, that allow acomputer to read such computer readable information.

Computer programs (also called computer control logic) are stored inmain memory 3106 and/or secondary memory 3112. Computer programs mayalso be received via communications interface 3124. Such computerprograms, when executed, enable the computer system to perform thefeatures of the present invention as discussed herein. In particular,the computer programs, when executed, enable the processor 3104 toperform the features of the computer system. Accordingly, such computerprograms represent controllers of the computer system.

Although specific embodiments of the invention have been disclosed,those having ordinary skill in the art will understand that changes canbe made to the specific embodiments without departing from the spiritand scope of the invention. The scope of the invention is not to berestricted, therefore, to the specific embodiments. Furthermore, it isintended that the appended claims cover any and all such applications,modifications, and embodiments within the scope of the presentinvention.

1. An information processing system comprising: a processor; a memory;an input/output subsystem; a bus coupled to the processor; the memory,and the input/output subsystem; and a cooling structure for cooling theprocessor, the cooling structure comprising: a compressible backingdisposed over the processor; a plurality of rigid copper elementsdisposed between the backing and the processor for providing a heat pathfrom the processor, wherein each of the plurality of rigid elementscomprises a spring configured to provide mechanical compliance in the x,y, and z directions and wherein interstitial spacing between each of theplurality of spring elements is sufficient for allowing the springelements to compress and elongate in alternate directions; a firstconformable heat-conducting layer disposed over the processor, whereinthe bottom end of the plurality of rigid elements is coupled to thefirst conformable heat-conducting layer; a second conformableheat-conducting, water-tight adhesion layer disposed between thecompressible backing and the plurality of rigid elements, wherein a topend of the plurality of rigid elements is coupled with the secondconformable heat-conducting layer; a liquid coolant disposed between thesecond conformable layer and the electronic device for cooling theplurality of rigid elements, wherein the liquid coolant is at least onematerial selected from a group consisting of: mercury, gallium, agallium alloy, an antifreeze, an alcohol, an oil, and water; and a sealfor containing the liquid coolant.